WASHINGTON — Republican Party officials were worried. So was the White House. But when Sen. Arlen Specter finally pulled away from challenger Pat Toomey in this week’s Pennsylvania’s Senate GOP primary — by just 1 percentage point — they stopped pacing the halls and chewing their fingernails.

For the Republican Party, the Specter win meant a better chance of triumphing in the general election, and thus a better chance of holding on to control of the U.S. Senate. And for the Bush White House, which actively campaigned for the senator, the victory meant that it would have a longtime incumbent as an ally in this important presidential battleground state.

But Specter’s victory was also a big win for another group: Republican moderates. In a race billed as a fight over the heart and soul of the GOP, Specter — who is pro-choice, who famously opposed conservative Supreme Court nominee Robert Bork in 1987, and who opposed President Clinton’s impeachment — bested his more conservative foe. “It's vital for the Republican Party that there be a center,” Specter said on Election Day.

In fact, true to form, Specter was already distancing himself from the White House just a day after winning his race. “I intend to retain my independent voice. It’s a voice I have always had and the 12 million people in Pennsylvania have not elected me to be a rubber stamp and I will speak out where I think the necessity calls for it.”

Yet while moderates won this week’s Specter-Toomey battle, there are plenty of signs suggesting that they are losing the ideological war. For instance, two of the most prominent Republican moderates in the House — Rep. Amo Houghton (who founded the centrist Republican Main Street Partnership) and Rep. Jack Quinn (a big supporter of organized labor), both from New York — announced this April that they were retiring.

And the number of moderate Senate Republicans, it seems, keeps on dwindling; in fact, these moderates can be counted on one hand. Susan Collins and Olympia Snowe of Maine. Lincoln Chafee of Rhode Island. And, of course, Arlen Specter.

“Specter said himself a couple of weeks ago that when he first came to the Senate, there were John Heinz, Lowell Weicker, and John Chafee, and a number of other liberal Republicans,” said Stephen Moore, the president of Club for Growth, the conservative group that worked aggressively to defeat Specter. “The old liberal Northeast Rockefeller Republican is dying out. I don’t think there is any question about it.”

Amy Walter, who tracks congressional races for the nonpartisan Cook Political Report, points out that the decline of House moderates really began in 2002. That year, for example, centrist Republican Connie Morella, who represented Maryland's Washington, D.C., suburbs, lost to Democratic challenger Chris Van Hollen. In Minnesota, moderate Democratic incumbent Bill Luther also lost to Republican John Kline. And in Florida, moderate incumbent Democrat Karen Thurman lost to Republican Ginny Brown-Waite in Florida.

What’s happening, Walter explains, is that centrist Democratic members from Red GOP-leaning areas are being replaced by Republicans, while centrist Republicans who live in Blue America are being replaced by Democrats.

Polarizing effectWalter and other observers say the decline in moderates has created a more polarized Congress, in which fewer members are willing to cast votes for the other side. “You are losing one of the few groups that are willing to work with other people to accomplish things,” said Eric Wortman, the communications director for the Blue Dog Coalition, which represents moderate Hill Democrats. “I think it’s a dangerous path to walk down.”

“I think it discourages some of the people who should be running and coming to Congress,” Walter added.

But not everyone agrees that moderation is a plus. “The Republicans win when they run as conservatives,” said the Club for Growth’s Moore. “That’s the message of Reagan and even [George W.] Bush. When they run on free-market issues, they win. When they run as RINOs (Republicans In Name Only) — as Bob Dole and Gerry Ford did — they lose.”

Yet while some are mourning the loss of moderates in American politics, others aren’t ready to pronounce them dead just yet. Sarah Chamberlain Resnick, the executive director of the Republican Main Street Partnership, points out that moderate Republicans like Melissa Brown and Charlie Dent won their congressional primaries in Pennsylvania; in fact, she notes that Dent is running for the very seat that was held by the conservative Pat Toomey. Resnick also cites the popularity and success of California Gov. Arnold Schwarzenegger. “Moderate Republicans, in my opinion, are very alive and kicking,” she said.

Two Dems for the listRep. Charlie Stenholm, a co-chair of the Blue Dog Coalition, adds two Democratic names to that alive-and-kicking list: Ben Chandler, who won a special congressional election in Kentucky earlier this year, and Stephanie Herseth, who’s leading in the polls in the race to fill South Dakota’s at-large congressional seat.

Indeed, Stenholm says, there will be as many as 40 elections this year — including his against Republican Randy Neugebauer in Texas — whose outcome will likely answer whether or not there’s a place for political moderates in Congress. “We are going to answer [that] question in live and living color,” Stenholm said.

So will Arlen Specter, who faces off against Democrat Joe Hoeffel in the Pennsylvania Senate general election. Will Specter hold on to his seat? Or will he be the latest GOP moderate incumbent to succumb to a Democrat in ablue state? After all, Al Gore beat Bush here in 2000, 51 percent to 46 percent.